Brake



Ma'y so, 1939. K. P. BRACE l 2,160,055

BRAKE Filed June 5, i957 6p V /z I. IIIIII /un'mll /6 /z ip 255.-/ X54 /50 FlEH v INVENTOR ATTORNEY 'Patented' May 30, 1939 UNITED ySTATES 2,100,055 BRAKE Kemper P. Brace', South Bend, Ind., assigner .to Bendix Products Corporation, South Bend, Ind.I a corporation oi Indiana t Application June 5, 1937, Serial No. 146,583

Claims.

This invention relates to brakes, and is illustrated as embodied in an internal expanding brake for an automobile wheel.

An object of the invention is to provide a device for automatically adjusting the brake for wear; as Vfor exampleby automatically determin- .ing the clearance ofthe brake shoe when the brake is released. A particular object is to provide a device of this character in which the workc ing parts are all housed within a cylinder or the equivalent.

Thelabove and other objects of the invention and various novel features of construction and arrangement, will be apparent from the follow- 5l ing description of the illustrativey embodiment shown in the accompanying drawing, in which: l Figure 1 is a partial section through the brake, just inside the head oi the brake drum, and showing the brake shoes in side elevation;

Figure 2 is a section throughthe novel auto-ll matic adjustment device, onthe line 2 -2 of Figure l; and

Figures 3 and i are sectionsthrough alternative forms of adjustment devices. y i While the devices embodying my invention can Vbe used equally well with standard anchoredshoe brakes, and other types of brakes, the brake shown in Figure 1 is of the shiftable anchorage type. It includes a rotatable drum It, at the u) open side of which isa support such as a backing plate i2, and Within which are the brake shoes I4 and i6. The shoes have between the notched ends of 'their webs, at one side of the brake, an anchor 55 post i8 carried by the backing plate, vadjacent 1 -`which is an applying device such as a floating.

lever having lugs 22 projecting between ends of the shoe Webs. The lever 20 may be actuated by a suitable Bowden type cable-and-conduit w control, the cable 24 of which extends through the backing plate and is connected tothe 1ever 20. l

The lever 2|) acts Jto apply the brake against th resistance of a 'return spring 26 tensioned ,5 between the shoes. APreferably an unbalancing spring 28 is tensioned between the anchor I8 and the secondary shoe (i. eddie shoe which is an- "chored' in forward braking).

The ends of the shoes opposite the anchor I8 50 are shown adjustably connected bymeans such as a. right-and-left threaded floating member 30 I threaded into-sockets 32 engaging the ends of the shoe webs, andaganst which the shoes are l heldy by a spring 34 tensioned between them and 55A also serving yieldingly to lock the member 30 by thereon.

(Ui. iwf-779.5)

engaging a serrated central peripheral rib 3 The rib 36 is accessible through a suitable opening in the backing plate, for engagement with a tool to turn the member `3ft to make the desired adjustment. s,

The present invention relates to an automatically adjustable device lill (Figuresl and 2) or hill (Figurel 3), or Mii (Figure 4), adapted to be connected at one' end to the brake shoe or its equivalent and at the other end to a stationary 10 part such as the backing plate i2. The automatically adjustable device fill includes a cylinder Q2, within which is a plunger M having a flange or head P36 at one end and having at its other end a stem 48 sliding through 35 a bearing sleeve 5|), adjustably threaded into the end of the cylinder t2 to serve also as an abutment engaged by the base of the plunger id after a lost motion. corresponding to the desired maximum shoe clearance. A spring 52 is compressed 20 between the abutment til and the flange t6.

The cylinder d2 projects `into the open end of a larger cylinder 5ft, and its exterior surface is held yieldingly frictionally gripped to the internal surface of the outer cylinder 5ft by means such as 25 a spring 56. The spring 5t is shown arranged .in a hollow boss 58 in the side wall 'of the cylinder 5ft, backed up by a threaded plug $0, and acts to force the cylinder i2 crcsswise of the cylinder dit.

The plunger stem i8 is connected, by means 30 such as a pivot pin 62, either to the shoe or to the backingL plate, while the bead of the outer v cylinder 5t is connected, by means such as. an-

other pivot pin 6E, to the backing plate or the shoe.

In operation, the normal application of the brake merely takes up the clearance between the abutment 5|) and-'the base of the plunger 44. When the brake wears so that the shoe moves further than'this when applied, the plunger 40 44 seats solidly against the abutment 50, and the excess shoe movement shifts the cylinder 42 axially within the cylinder 54. When the brake is released the head 46 seats against the closed end of the cylinder .42. 46

In Figure 3, parts corresponding to parts in Figure 2 are designated by the same reference characters increased by 100. In this embodiment, a looped spring |54 projects into the open end of the'cylinder |42 and frictionally expansibly 60 I' grips a friction sleeve 10 threaded thereinto.-

AThe plunger |44 engages, after its lost motion,

-a shoulder |50 on the cylinder |42; and the spring 52 is replaced by a block 452 ofv rubber. j When the lbrake-is' rieased.- the plunger |44 56 'seats against the end of the'sleeve 10. In this case it is the sleeve 10, rather than abutment 50 as in Figure 2, which is adjusted to change the clearance ofthe shoe.

In Figure 4, parts corresponding to parts in Figure 2 are indicated by the same reference characters increased by 200. In this case, plunger 244 after its lost motion seats against the end 25D of the cylinder 242.

The plunger 244 is formed with an axial socket slidably seated on the reduced end of a stop member 82 carried by a plug 80 yadjustably threaded into the end of the cylinder 242. The exterior surface of the plunger 242 is frictionally gripped between leaf springs 256 each welded or otherwise secured at one end to the interior surface of the outer cylinder 254. When the brake is released, the plunger 2.44 seats against the' end of the "large-diameter portion of the stop 82.

In all three embodiments, after the desired shoe clearance is taken up, excess shoe movement serves to increase the eective length of the automatic adjustment device, so that when the brake is again released the shoe clearance will be back to normal. In all three embodiments the normal shoe clearance can be varied by adjusting abutment 5l), or sleeve 10, or plug 80.

While several illustrative embodiments have been described in detail, it is not my intention to limit the scope of the invention to those particular embodiments, or otherwise than by the terms of the appended claims.

1. An automatically,l adjustable deviceI constructed and arranged to be acted on by a brake shoe or the like and :comprising a cylinder having arranged therein a plunger having a predetermined free lost motion relatively to the cylinder corresponding to the desired maximum ap-` plying ymovement of said shoe and having connecting 'meana and connecting means frictionally gripping the surface of said cylinder, one of said connecting means being adapted to be connected to a brake shoe and the other being adapted to be connected to a backing plate.

`2. An automatically adjustable `device constructed and arranged to be acted on by a brake shoe or the like and comprising a cylinder hav` ing arranged therein a plungervhaving a lost motion relatively to the cylinder corresponding to the desired maximum applying movement of said shoe and having means for connecting it to the shoe or the backing plate, and a larger cylinder into which the rst cylinder extends and which is adapted to be connected to the backing plate or the shoe and which has means frictionally gripping the exterior surface of said rst cylinder.

. 3. An automatically adjustable device constructed and arranged to be acted on by a brake shoe or the like and comprising a cylinder having arranged therein a plunger having a lost motion relatively to the cylinder corresponding to the desired maximum applying 'movement of said shoe and having means for connecting it to the shoe or the backing plate, and a larger cylinder into which the iirst cylinder extends and which is adapted to be connected to the backing plate or the shoe and which is provided with means yieldingly urging its interior surface into frictional engagement with the exterior surface of the first cylinder.

4. An automatically adjustable device con,- structed and arranged to be acted on Vby a brake shoe or the like and comprising a cylinder having arranged therein a plunger having a lost motion relatively to the cylinder corresponding to the desired maximum applying movement of said shoe` and having means for connecting it to .the shoe or the backing plate, and a larger cylinder into which the first cylinder extends and which is adapted to be connected to the backing plate or the lshoe and which is provided with leaf springs yieldingly gripping the exterior surface of the rst cylinder.

5. An ,automatically adjustable device con' structed and arranged to be acted on by a brake shoe or the like and comprising a cylinder having arranged therein a plunger having a lost motion relatively to the cylinder corresponding to the desired maximum applying movement of said shoe and having means for connecting it to the shoe or the backing plate, and a looped spring member extending into the other end of the cylinder and frictionally expansibly gripping the interior surface of said cylinder and which is adapted to be rfmnected to the backing plate or the shoe.

KEMPER P. BRACE. 

